JP4482861B2 - Rare earth magnet powder excellent in magnetic anisotropy and thermal stability and method for producing the same - Google Patents

Description

  The present invention relates to a rare earth magnet powder excellent in magnetic anisotropy and thermal stability and a method for producing the same.

  When M is one or more of Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C, and Si, it is expressed in atomic% (hereinafter referred to as “%”). ,% Represents atomic%), one or more of Y-containing rare earth elements: 10 to 20%, Co: 0 to 50%, B: 3 to 20%, M: 0 to 5% A rare earth magnet alloy raw material hydride powder having a component composition consisting of Fe and inevitable impurities, and Dy, Tb simple substance, alloy, compound, or hydride of them (single substance, alloy, compound) A method for producing a rare earth magnet powder excellent in magnetic anisotropy by mixing to produce a mixed powder, diffusing and heating the mixed powder, and dehydrogenating from the diffusively heated mixed powder is known. Rare earth magnet alloy raw material hydride powder The raw material was heated to a predetermined temperature from room temperature to less than 500 ° C. in a hydrogen atmosphere, or heated and held for hydrogen absorption treatment, and then hydrogen pressure: 500 to 1000 ° C. in a hydrogen atmosphere of 10 to 1000 kPa. Is heated and held at a predetermined temperature within the above range to absorb hydrogen into the rare earth magnet alloy raw material to promote decomposition by phase transformation, followed by hydrogen absorption / decomposition treatment. The rare earth magnet alloy raw material at a predetermined temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa and an inert gas Is kept in a mixed gas atmosphere, and heat treatment in reduced-pressure hydrogen is performed while leaving a portion of the hydrogen in the rare earth magnet alloy raw material, followed by introduction of Ar gas and cooling to room temperature. It is known to manufacture by (see Patent Document 1).

In addition, the magnetic anisotropic HDDR magnet powder, which is a rare earth magnet powder, is obtained by subjecting a rare earth magnet alloy raw material to hydrogen absorption treatment and then a predetermined temperature within a range of 500 to 1000 ° C. in a hydrogen atmosphere of hydrogen pressure: 10 to 1000 kPa. The rare-earth magnet alloy raw material subjected to hydrogen absorption / decomposition treatment that absorbs hydrogen to the rare-earth magnet alloy raw material to promote decomposition by phase transformation by heating and holding at 500 to 500 to Since dehydrogenation treatment is performed by holding in a vacuum at a predetermined temperature within a range of 1000 ° C., the main phase is an R ₂ Fe ₁₄ B type intermetallic compound phase having a substantially tetragonal structure. The recrystallized grains have recrystallized textures adjacent to each other, and the recrystallized texture is a shape in which the ratio (b / a) of the shortest grain size a to the longest grain size b of each recrystallized grain is less than 2. Recrystallization It is known that the grains have a basic structure of magnetic anisotropic HDDR magnet powder in which 50% by volume or more of the total recrystallized grains are present and the average recrystallized grain size of the recrystallized grains is 0.05 to 5 μm. (See Patent Document 2).
JP 2002-93610 A Japanese Patent No. 2576672

  In recent years, rare earth magnet powders with higher magnetic anisotropy have been demanded in the electric and electronic industries, and particularly in the automobile industry, the development of electric cars has been active, and the development of motors for use in electric cars has been actively conducted. Yes. The motor mounted on this electric vehicle is often placed in an environment where it is particularly easily heated because it may be installed in the vicinity of a small gasoline engine or may be left in the sun. Therefore, it is possible to produce a motor component with excellent heat resistance and magnetic characteristics. Rare earth magnet powder having magnetic anisotropy with excellent coercive force and residual magnetic flux density and excellent thermal stability. Is required.

Therefore, the present inventors have studied to obtain a rare earth magnet powder having more excellent magnetic anisotropy and thermal stability. As a result, the research results described in the following (ii) to (ha) were obtained.
(Ii) (a) In atomic% (hereinafter,% indicates atomic%) and R (where R represents one or more of rare earth elements including Y, excluding Dy and Tb). The same shall apply hereinafter): 5 to 20%, containing one or two of Dy and Tb in an amount of 0.01 to 10%, and B: 3 to 20%, with the balance being composed of Fe and inevitable impurities, A rare earth magnet powder having an average powder particle size: 10 to 1000 μm,
This rare earth magnet powder is covered with 70% or more of the entire surface with a layer having a thickness of 0.05 to 50 μm and a high content of one or two of Dy and Tb (hereinafter referred to as Dy-Tb rich layer). One or two concentrations of Dy and Tb in the Dy-Tb rich layer have a maximum detection intensity by the wavelength dispersion type X-ray spectroscopy of one or two of Dy and Tb. A rare earth magnet powder that is 1.2 to 5 times the average detected intensity at the center within a range of 1/3;
(B) R: 5 to 20%, one or two of Dy and Tb are contained 0.01 to 10%, B: 3 to 20%, M: 0.001 to 5%, with the balance being Fe and A rare earth magnet powder having a component composition consisting of inevitable impurities and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle by the maximum detection intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
(C) R: 5 to 20%, Co: 0.1 to 50%, one or two of Dy and Tb are contained in an amount of 0.01 to 10%, B: 3 to 20%, the balance being Fe and A rare earth magnet powder having a component composition consisting of inevitable impurities and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle by the maximum detection intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
(D) R: 5 to 20%, one or two of Dy and Tb are 0.01 to 10%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5 A rare earth magnet powder having a component composition consisting of Fe and inevitable impurities, and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle with the maximum detected intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
The rare earth magnet powders described in the above (a) to (d) all have magnetic anisotropy and thermal stability that are superior to the conventional rare earth magnet powder described in Patent Document 1.
(B) Each of the rare earth magnet powders has a recrystallized texture in which recrystallized grains mainly having an R ₂ Fe ₁₄ B type intermetallic compound phase having a tetragonal structure are adjacent to each other. The recrystallized texture has 50% by volume or more of recrystallized grains having a shape in which the ratio (b / a) of the shortest particle diameter a and the longest particle diameter b of each recrystallized grain is less than 2, In addition, the research result that the average recrystallized grain size of the recrystallized grains has a basic structure of magnetic anisotropic HDDR magnet powder having a size of 0.05 to 5 μm was obtained.
(Ii) These rare earth magnet powders having magnetic anisotropy and thermal stability can produce rare earth magnets by a usual method.

In order to produce the rare earth magnet powder having the more excellent magnetic anisotropy and thermal stability,
(A) In the conventional method for producing a rare earth magnet powder excellent in magnetic anisotropy, the rare earth magnet alloy raw material is pulverized in a normal inert gas atmosphere until the average particle size becomes 10 to 1000 μm. An alloy raw material powder was prepared, and a Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm was added to the rare earth magnet alloy raw material powder. .01-5 mol% added and mixed to make a mixed powder,
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment for absorbing and decomposing hydrogen by absorbing the mixed powder by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding it in a hydrogen gas atmosphere of 10 to 1000 kPa. Similarly, if necessary, the mixed powder subjected to the hydrogen absorption / decomposition treatment is placed in an inert gas atmosphere at a predetermined temperature within a range of inert gas pressure: 10 to 1000 kPa and temperature: 500 to 1000 ° C. The intermediate heat treatment is performed by holding, and then, if necessary, the mixed powder subjected to the intermediate heat treatment is subjected to a predetermined temperature within a range of 500 to 1000 ° C. , Absolute pressure: 0.65 to less than 10 kPa in hydrogen atmosphere or hydrogen partial pressure: less than 0.65 to 10 kPa in a mixed gas atmosphere of hydrogen and inert gas to leave part of the hydrogen in the mixed powder Then, heat treatment is performed in hydrogen under reduced pressure, and then hydrogen is forcibly released by promoting the phase transformation by maintaining a vacuum atmosphere at an ultimate pressure of 0.13 kPa or less at a predetermined temperature within a range of 500 to 1000 ° C. It can be produced by applying a dehydrogenation treatment, then cooling and crushing.
(B) If necessary, absorb the hydrogen by raising the temperature of the rare earth magnet alloy raw material from room temperature to a temperature of less than 500 ° C or holding it in a hydrogen gas atmosphere of pressure: 10 to 1000 kPa. After the hydrogen absorption treatment, a rare earth magnet alloy raw material powder (hereinafter referred to as a hydrogen absorbing rare earth magnet alloy raw material powder) that has been pulverized to an average powder particle size of 10 to 1000 μm and treated with hydrogen absorption is prepared. And
To this hydrogen-absorbing rare earth magnet alloy raw material powder, 0.01 to 5 mol of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added. % To make a hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. The hydrogen-containing raw material mixed powder subjected to hydrogen absorption / decomposition treatment, and then subjected to hydrogen absorption / decomposition treatment, if necessary, within the range of inert gas pressure: 10 to 1000 kPa, temperature: 500 to 1000 ° C. An intermediate heat treatment is carried out by maintaining it in an inert gas atmosphere at a predetermined temperature, and subsequently, if necessary, the hydrogen-containing raw material mixed powder subjected to the intermediate heat treatment is subjected to a predetermined heat treatment within a range of 500 to 1000 ° C. In a hydrogen atmosphere at an absolute pressure of less than 0.65 to 10 kPa or a mixed gas atmosphere of hydrogen and an inert gas at a temperature of less than 0.65 to 10 kPa at a temperature The hydrogen-containing raw material mixed powder is subjected to a heat treatment in a reduced pressure hydrogen while retaining a part of the hydrogen-containing raw material mixed powder, and then, at a predetermined temperature in the range of 500 to 1000 ° C., an ultimate pressure: 0.13 kPa or less in a vacuum atmosphere It can also be produced by forcibly releasing hydrogen by holding it in a dehydrogenation treatment that promotes phase transformation, followed by cooling and crushing.

The rare earth magnet alloy raw material is atomic% (hereinafter,% indicates atomic%),
R ′ (where R ′ represents one or more of rare earth elements including Y, including cases where one or two of Dy and Tb are not included; the same applies hereinafter): 10 to 20% B: a rare earth magnet alloy raw material having a composition containing 3 to 20%, the balance being Fe and inevitable impurities,
R ′: 10 to 20%, B: 3 to 20%, M (where M is Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C And one or more of Si, the same shall apply hereinafter): a rare earth magnet alloy raw material having a component composition of 0.001 to 5%, the balance being Fe and inevitable impurities,
R ′: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities,
Or, R ′: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, with the balance being composed of Fe and inevitable impurities A rare earth magnet alloy raw material is preferred.

This invention was made based on these research results,
(1) R (where R is a rare earth element including Y except for Dy and Tb; the same applies hereinafter): 5 to 20%, one or two of Dy and Tb being 0.01 to 10%, B: a rare earth magnet powder containing 3 to 20%, the balance having a component composition consisting of Fe and inevitable impurities, and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with 70% or more of the entire surface with a layer having a thickness of 0.05 to 50 μm and a high content of one or two of Dy and Tb (hereinafter referred to as Dy-Tb rich layer). One or two concentrations of Dy and Tb in the Dy-Tb rich layer have a maximum detection intensity by the wavelength dispersion type X-ray spectroscopy of one or two of Dy and Tb. A rare earth magnet powder that is 1.2 to 5 times the average detected intensity at the center within a range of 1/3;
(2) R: 5 to 20%, one or two of Dy and Tb are contained 0.01 to 10%, B: 3 to 20%, M: 0.001 to 5%, with the balance being Fe and A rare earth magnet powder having a component composition consisting of inevitable impurities and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle with the maximum detected intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
(3) R: 5 to 20%, Co: 0.1 to 50%, one or two of Dy and Tb are contained in an amount of 0.01 to 10%, B: 3 to 20%, the balance being Fe and A rare earth magnet powder having a component composition consisting of inevitable impurities and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle with the maximum detected intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
(4) R: 5 to 20%, one or two of Dy and Tb are 0.01 to 10%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5 A rare earth magnet powder having a component composition consisting of Fe and unavoidable impurities, and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and having a large content of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle with the maximum detected intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. Rare earth magnet powder which is 1.2 to 5 times the average detected intensity of the central part in
(5) A rare earth magnet obtained by bonding the rare earth magnet powder excellent in magnetic anisotropy and thermal stability described in (1), (2), (3) or (4) with an organic binder or a metal binder,
(6) A rare earth magnet obtained by hot pressing or hot isostatic pressing the rare earth magnet powder having excellent magnetic anisotropy and thermal stability described in (1), (2), (3) or (4). ,
(7) Rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. .1-50 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in 0.01-5 mol% and mixed to produce a mixed powder;
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(8) The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere until the average particle size becomes 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. .1-50 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in 0.01-5 mol% and mixed to produce a mixed powder;
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, an intermediate heat treatment is performed by holding the mixed powder subjected to hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(9) The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. .1-50 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in 0.01-5 mol% and mixed to produce a mixed powder;
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, the mixed powder that has been subjected to hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere of hydrogen and an inert gas, heat treatment in reduced pressure hydrogen is performed while leaving some hydrogen in the mixed powder,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(10) Rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. .1-50 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in 0.01-5 mol% and mixed to produce a mixed powder;
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, an intermediate heat treatment is performed by holding the mixed powder subjected to hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Subsequently, the mixed powder that has been subjected to the intermediate heat treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere with the active gas, a heat treatment in reduced-pressure hydrogen is performed while leaving some hydrogen in the mixed powder,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(11) The rare earth magnet alloy raw material described in the above (7), (8), (9) or (10) is a rare earth which is homogenized in a vacuum or an Ar gas atmosphere at a temperature of 600 to 1200 ° C. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, which is a magnet alloy raw material,
(12) Hydrogen absorption treatment for absorbing hydrogen by raising the temperature of the rare earth magnet alloy raw material from room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere of pressure: 10 to 1000 kPa After the application, a rare earth magnet alloy raw material powder (hereinafter referred to as a hydrogen absorbing rare earth magnet alloy raw material powder) that has been pulverized to an average powder particle size of 10 to 1000 μm and hydrogen-absorbed is prepared.
To this hydrogen-absorbing rare earth magnet alloy raw material powder, 0.01 to 5 mol of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added. % To make a hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(13) Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added to the hydrogen-absorbing rare earth magnet alloy raw material powder in an amount of 0.01 to Add 5 mol% and mix to make hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the hydrogen-containing raw material mixed powder subjected to the hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(14) Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added to the hydrogen-absorbing rare earth magnet alloy raw material powder in an amount of 0.01 to Add 5 mol% and mix to make hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, the hydrogen-containing raw material mixed powder that has been subjected to hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of 0.65 to A heat treatment in reduced-pressure hydrogen is performed while leaving part of the hydrogen in the hydrogen-containing raw material mixed powder by maintaining in a mixed gas atmosphere of hydrogen and inert gas of less than 10 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(15) Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added to the hydrogen-absorbing rare earth magnet alloy raw material powder in an amount of 0.01 to Add 5 mol% and mix to make hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the hydrogen-containing raw material mixed powder subjected to the hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa,
Subsequently, the hydrogen-containing raw material mixed powder subjected to the intermediate heat treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere of hydrogen and an inert gas, a hydrogen-containing raw material mixed powder is subjected to heat treatment in hydrogen under reduced pressure while leaving part of the hydrogen in the mixed powder.
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by maintaining a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. under an ultimate pressure of 0.13 kPa or less to promote phase transformation. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability to be crushed;
(16) The rare earth magnet alloy raw material for producing the hydrogen-absorbing rare earth magnet alloy raw material powder described in (12), (13), (14) or (15) is a vacuum or an Ar gas atmosphere at a temperature of 600 to A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized in that it is a rare earth magnet alloy raw material homogenized under conditions of maintaining at 1200 ° C.
(17) Magnetic produced by the method described in (7), (8), (9), (10), (11), (12), (13), (14), (15) or (16) A method for producing a rare earth magnet, comprising bonding rare earth magnet powder excellent in anisotropy and thermal stability with an organic binder or a metal binder.
(18) Magnetic produced by the method described in (7), (8), (9), (10), (11), (12), (13), (14), (15) or (16) Production of a green compact by molding rare earth magnet powder excellent in anisotropy and thermal stability, and manufacturing the rare earth magnet by hot pressing or hot isostatic pressing the green compact at a temperature of 600 to 900 ° C. Method,
(19) The rare earth magnet alloy raw material according to (7), (8), (9), (10), (11), (12), (13), (14), (15) or (16) , In atomic% (hereinafter,% indicates atomic%),
R ′ (where R ′ represents a rare earth element containing Y. The same shall apply hereinafter): 10 to 20%, B: 3 to 20%, the remainder comprising a component composition consisting of Fe and inevitable impurities material,
R ′: 10 to 20%, B: 3 to 20%, M: 0.001 to 5%, a rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities,
R ′: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities, or R ′: 10 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, a magnetic material that is a rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities. It is characterized by a method for producing a rare earth magnet powder excellent in anisotropy and thermal stability.

  Preparation of rare earth magnet alloy raw material powder or hydrogen-absorbing rare earth magnet alloy raw material powder → Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder 0.01 ~ 5 mol% added and mixed to produce mixed powder → hydrogen absorption treatment → hydrogen absorption / decomposition treatment → intermediate heat treatment as needed → heat treatment in reduced pressure hydrogen as necessary → dehydration rare earth according to the present invention The rare earth magnet powder obtained by the magnet powder manufacturing method is excellent in magnetic anisotropy and thermal stability, and has excellent industrial effects.

The composition and structure of the rare earth magnet powder of the present invention, and the rare earth magnet alloy raw material powder or the hydrogen absorbing rare earth magnet alloy raw material powder in the method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability of the present invention The reason why the addition amount and the production conditions for adding the hydride powder of Tb, the hydride powder of Tb, or the hydride powder of the Dy-Tb binary alloy are limited as described above will be described.
(A) Rare earth magnet powder (i) Reason for limitation of component composition R:
R is a rare earth element (except for Dy and Tb) mainly composed of Nd and containing trace amounts of Y, Pr, Sm, Ce, La, Er, Eu, Gd, Tm, Yb, Lu, Ho and the like. However, if the content is less than 5%, the coercive force is lowered. On the other hand, if the content exceeds 20%, the saturation magnetization is lowered and none of the desired magnetic properties can be obtained. Therefore, the content of R is set to 5 to 20%.
Dy and Tb:
The reason why the content of one or two of Dy and Tb is limited to 0.01 to 10% (more preferably 0.3 to 4%) is that one or two of Dy and Tb is 0.01 Even if the content is less than 10%, desired effects excellent in magnetic anisotropy and thermal stability cannot be obtained. On the other hand, if the content exceeds 10%, anisotropy is reduced and sufficient magnetic properties are obtained. This is because it is not preferable.
B:
If the B content is less than 3%, the coercive force is lowered. On the other hand, if it exceeds 20%, the saturation magnetization is lowered and none of the desired magnetic properties can be obtained. Therefore, the content of B is set to 3 to 20%.
Co:
Co is added as necessary in order to prevent the rare-earth magnet alloy from being isotropic. However, if the content is less than 0.1%, the desired effect cannot be obtained. Since the coercive force and the saturation magnetization are lowered, high characteristics cannot be obtained even if anisotropic. Therefore, the Co content in the rare earth magnet alloy raw material used in the rare earth magnet powder and the rare earth magnet powder manufacturing method of the present invention is set to 0.1 to 50% (more preferably 5 to 30%).
M (one or more of Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C, and Si):
M is added as necessary to further improve the coercive force and the residual magnetic flux density, but if the content is less than 0.001%, the desired effect cannot be obtained, while adding over 5%. This is not preferable because the coercive force and the residual magnetic flux density are lowered. Therefore, the content of M is set to 0.001 to 5% or less.
(Ii) Reason for limitation of tissue Maximum detected intensity by line analysis of wavelength dispersion X-ray spectroscopy:
The maximum detected intensity of one or two kinds of Dy or Tb near the surface is scanned across the powder cross section by wavelength analysis of wavelength dispersive X-ray spectroscopy, and 1 / of the particle size near the center of the powder. The average detected intensity in the range of 3 is obtained and set as the intensity near the center, and the maximum detected intensity of one or two kinds of Dy or Tb of the peak near the surface is obtained as a ratio to the average detected intensity. In some cases, a place where the detection intensity of one or two of Dy or Tb is partially extremely large appears. In many cases, this is because a rare earth-rich phase exists, and this phase is characterized by Dy or Tb. In addition to one or two of the above, the detection intensities of one or two of Nd or Pr are simultaneously increased. Since such a phase is an inevitable layer in the present invention, it is excluded from the object of evaluation of the maximum detection intensity. Here, when the maximum detected intensity by one or two types of wavelength-dispersive X-ray spectroscopy of Dy or Tb is less than 1.2 times, the difference in anisotropic magnetic field between the surface and the inside of the powder is Since it is small, the effect of achieving both a large coercive force due to a high anisotropic magnetic field on the surface and a large internal anisotropy cannot be obtained. Further, when the detection intensity exceeds 5 times, the magnetic flux density in the region near the surface is greatly reduced. Therefore, the detection intensity of one or two types of wavelength-dispersive X-ray spectroscopy of Dy or Tb in the region was set to 1.2 to 5 times (preferably 1.3 to 4 times) the internal detection intensity.
Thickness from the surface of the Dy-Tb rich layer:
The depth from the surface of the region (Dy-Tb rich layer) having a high content of one or two of Dy or Tb present on the surface of the rare earth magnet powder is determined by the line analysis of wavelength dispersive X-ray spectroscopy. The width of a portion where the intensity of the detected peak is 1.2 times or more of the average detected intensity near the center of the detected peak is set to one or two of Dy or Tb. It is determined as the depth from the surface of the region where the seed content is large. In addition, when the scanned location is a location where a Dy-Tb rich phase with one or two detection strengths of Dy or Tb being extremely large is present, the depth from the surface is evaluated. Shall be excluded. Here, one or two of Dy or Tb replaces the R atom of the R ₂ (Fe, Co) ₁₄ B-type crystal particle near the surface, and (R, (Dy, Tb)) ₂ (Fe, Co) ₁₄ B type phase is considered to be formed, and the effect of the present invention is to replace one or more crystal grains on the surface so that one or two kinds of Dy or Tb are more than one inside. However, if the thickness of the Dy-Tb rich layer, which is a region where the content of one or two of Dy or Tb is large, is less than 0.05 μm, the desired effect cannot be obtained. In addition, when the thickness exceeds 50 μm, the volume of the region where the content of one or two of Dy or Tb is large and the coercive force is large affects the region of high anisotropy inside, and the anisotropic of the whole powder. Will significantly reduce the performance. Therefore, the depth from the surface of the Dy-Tb rich layer is set to 0.05 to 50 μm (desirably 1 to 30 μm).
Surface coverage of Dy-Tb rich layer:
The surface coverage of the region (Dy-Tb rich layer) in which the content of one or two of Dy or Tb is large is 5 by changing the scanning position for one powder cross section in the line analysis of wavelength dispersive X-ray spectroscopy. Perform line analysis more than once, and traverse the powder surface by the number of powder surfaces whose total detected intensity near the surface of one or two types of Dy or Tb powder is more than 1.2 times near the center. As a percentage of the number of times In addition, when the scanned place is a place where a rare earth-rich phase with one or two detection strengths of Dy or Tb that is extremely extremely large exists, it is excluded from counting. Here, the powder surface is covered with a region having a large amount of one or two of Dy or Tb, which is an element that has a large anisotropic magnetic field and is less likely to be oxidized than Nd. It has both magnetic force and anisotropy, and excellent oxidation resistance can be obtained. However, when the area covering the surface is less than 70%, a sufficiently large coercive force cannot be obtained, and oxidation resistance is insufficient. Sufficient thermal stability and heat resistance cannot be obtained. Therefore, the area covered by the region having a high content of one or two of Dy or Tb was set to 70% or more (preferably 80% or more) of the entire powder surface.

The rare earth magnet powder of the present invention described above is retained as a powder because the anisotropic magnetic field of one or two types of Dy or Tb near the surface inside the powder (Dy-Tb rich layer) is higher than that near the center. The magnetic force is improved, and Dy and Tb are relatively hardly oxidized, and the oxidation resistance as a powder is improved. Therefore, it is considered that the thermal stability and heat resistance of the powder are improved. Furthermore, since one or two regions having a large amount of Dy or Tb (Dy-Tb rich layer) are limited to the vicinity of the surface of the powder, the anisotropy of the entire powder is hardly reduced. It is considered that high anisotropy is compatible.
(B) Reasons for limiting the production conditions in the method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability described in (7), (8), (9), (10) and (11):
The reason why the rare earth magnet alloy raw material is pulverized to an average particle size of 10 to 1000 μm (more preferably 50 to 400 μm) is that the average particle size is less than 10 μm and is finely pulverized in an inert gas atmosphere. Therefore, it is inevitable that the alloy is oxidized due to heat generated during pulverization, and the coercivity of the rare earth magnet powder finally obtained by this oxidation is not preferable. On the other hand, the average particle size is less than 1000 μm. If it is larger, the Dy, Tb or Dy-Tb binary alloy cannot be diffused to the center of the rare earth magnet alloy raw material powder, resulting in a non-uniform composition, and finally the rare earth magnet powder obtained by crushing. This is because the easy axis of magnetization in one powder particle becomes difficult to align and the magnetic anisotropy decreases, which is not preferable.

  To this rare earth magnet alloy raw material powder, 0.01 to 5 mol% of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added. And mixed to produce a mixed powder, and this mixed powder absorbs hydrogen by raising the temperature from room temperature to a temperature of less than 500 ° C. or holding it in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption treatment, followed by hydrogen absorption in which the mixed powder absorbs and decomposes by raising the temperature to a temperature in the range of 500 to 1000 ° C. and holding it in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa.・ A decomposition process is performed, and then hydrogen is forcibly released by maintaining in a vacuum atmosphere at a temperature within a range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, thereby causing phase transformation. Dehydrogenated subjected to prompt, then cooled and pulverized, more excellent rare-earth magnet powder in the magnetic anisotropy and thermal stability is to be obtained.

  The rare earth magnet alloy raw material powder is mixed with Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder, and mixed to obtain a hydrogen absorption treatment. Absorption / decomposition treatment followed by dehydrogenation treatment yields a rare earth magnet powder with more excellent magnetic anisotropy and thermal stability. The reasons for this can be considered as follows.

  Recent research has shown that rare earth magnet powders are made anisotropic by hydrogen absorption, further hydrogen absorption / decomposition, and then dehydrogenation (this process is generally referred to as HDDR process). It has become clear that the reaction at the stage of hydrogen absorption and decomposition is important. On the other hand, when one or two of Dy or Tb is added to a rare earth magnet alloy in an attempt to improve the coercive force in order to improve the thermal stability, it appears in the literature (Japanese Patent Laid-Open No. 9-165601). However, the anisotropy decreases and a sufficient energy product cannot be obtained. This is because when the rare earth magnet alloy contains one or two of Dy or Tb in a large amount, the reaction of the hydrogen absorption / decomposition treatment described above is affected, and it is formed by the hydrogen absorption / decomposition reaction. It seems that this is because the state does not satisfy the anisotropy condition.

However, the rare earth magnet alloy raw material powder obtained by pulverization in a normal inert gas atmosphere as in the present invention, Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride When the mixed powder obtained by adding and mixing the powder is subjected to hydrogen absorption / decomposition treatment, the decomposition reaction at that time is caused by the rare earth element hydride formed from the rare earth magnet alloy, and the remainder is Fe or (Fe, Co) and Fe ₂ B are decomposed into a phase based on Fe ₂ B. Therefore, the same rare earth element Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is Since it is not involved in this decomposition reaction, only the rare earth magnet alloy raw material powder is decomposed, so that the hydrogen absorption / decomposition reaction occurs as in the case where a large amount of one or two of Dy or Tb is added to the rare earth magnet alloy. In State formed me is not a state that does not satisfy the anisotropic conditions.

Next, when dehydrogenation is performed from this state, a phase based on R hydride, Fe or (Fe, Co) and Fe ₂ B decomposed in the rare earth magnet alloy raw material powder reacts to produce R ₂ Fe ₁₄ B In addition, a Dy hydride powder, a Tb hydride powder or a hydride powder of a Dy-Tb binary alloy also releases one of Dy or Tb by releasing hydrogen. Since the two types of atoms diffuse throughout the surface of the rare earth magnet alloy raw material powder and subsequently diffuse toward the inside of the rare earth magnet alloy raw material powder, the phase based on R ₂ Fe ₁₄ B finally formed is Compared to the original rare earth magnet alloy raw material powder, the content of one or two kinds of Dy or Tb is increased, and the content of one or two kinds of Dy or Tb in the vicinity of the surface in the powder particles is contained in the powder particles. Heart of As a result, the coercive force is improved and the temperature coefficient of the coercive force is reduced, so that the thermal stability is improved. On the other hand, since the condition for anisotropy is satisfied at the stage of hydrogen absorption / decomposition reaction, anisotropy actually occurs by dehydrogenation, resulting in a large coercive force and anisotropy. The reason is that an excellent rare earth magnet powder can be obtained.

In this invention, 0.01 to 50 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added to the rare earth magnet alloy raw material powder. 5 mol% is added and mixed to prepare a mixed powder, and this mixed powder is further heated to maintain a predetermined temperature within a range of temperature: 500 to 1000 ° C. in a hydrogen gas atmosphere of pressure: 10 to 1000 kPa. By absorbing and decomposing the raw material, the raw material absorbs hydrogen to promote phase transformation and decompose, but Dy hydride powder added to the rare earth magnet alloy raw material powder, Tb hydride powder or The reason why the average particle size of the hydride powder of the Dy-Tb binary alloy is limited to 0.1 to 50 μm is that Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder If the average particle size is less than 0.1 μm, the oxidation becomes severe and the handling becomes very difficult, which is not preferable. On the other hand, if the average particle size exceeds 50 μm, it is not preferable to include Dy, Tb or Dy-Tb binary in the rare earth magnet powder. Since the alloy alloy phase or the compound phase containing these elements excessively segregates and cannot be uniformly diffused, the average particle size of these hydride powders is 0.1 to 50 μm (more preferably 1 to 10 μm). Determined.
Moreover, the reason for limiting the amount of addition to 0.01 to 5 mol% is that if it is less than 0.01 mol%, the effect of improving the coercive force is not sufficient, while if it exceeds 5 mol%, the anisotropy decreases. Therefore, it is not preferable because sufficient magnetic properties cannot be obtained. Therefore, the addition amount of the hydride powder of Dy, the hydride powder of Tb or the hydride powder of the Dy-Tb binary alloy is 0.01 to 5 mol% (more preferably 0.3 to 3 mol%). Determined.

  The pressure in the hydrogen absorption treatment is a known condition for raising the temperature from room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere of 10 to 1000 kPa, and maintaining it after raising the temperature. The pressure in the hydrogen absorption / decomposition treatment step to be performed: In a hydrogen gas atmosphere of 10 to 1000 kPa, the temperature is maintained at a predetermined temperature in the range of 500 to 1000 ° C., and the conditions are already known. Since it is not a new condition, explanation of the reason for limitation will be omitted.

  After such hydrogen absorption / decomposition treatment, intermediate heat treatment is performed as necessary. This intermediate heat treatment is a step of promoting anisotropy at an appropriate speed by changing the atmosphere to an inert gas atmosphere by an inert gas flow. This intermediate heat treatment is performed under a condition of maintaining a predetermined temperature within a temperature range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa. If the pressure of the inert gas atmosphere in the intermediate heat treatment is less than 10 kPa, the anisotropy becomes too fast and causes a decrease in the coercive force. On the other hand, if it exceeds 1000 kPa, the anisotropy hardly progresses and the residual This is not preferable because it causes a decrease in magnetic flux density.

  After performing an intermediate heat treatment as necessary, a heat treatment in reduced-pressure hydrogen is further performed as necessary. This heat treatment in hydrogen under reduced pressure is carried out in a hydrogen atmosphere with an absolute pressure of less than 0.65 to 10 kPa (preferably 2 to 8 kPa) or a hydrogen partial pressure of less than 0.65 to 10 kPa (preferably Is a step of heat-treating while maintaining a part of hydrogen in the mixed powder by maintaining in a mixed gas atmosphere of 2 to 8 kPa) hydrogen and an inert gas. By performing the heat treatment in hydrogen under reduced pressure, the coercive force and the residual magnetic flux density can be further improved.

  If necessary, dehydrogenation is performed after intermediate heat treatment and heat treatment in hydrogen under reduced pressure. The dehydrogenation process is a process that forcibly releases hydrogen from the mixed powder by maintaining a vacuum atmosphere at an ultimate pressure of 0.13 kPa or less, thereby promoting further phase transformation. The ultimate pressure is maintained in a vacuum atmosphere of 0.13 kPa or less because dehydrogenation is not sufficiently performed at an ultimate pressure exceeding 0.13 kPa.

The cooling performed after the dehydrogenation is performed by flowing an inert gas (Ar gas) to room temperature. After cooling, it is crushed into rare earth magnet powder. The rare earth magnet powder obtained by pulverization has very little residual internal stress, so that it does not need to be heat-treated. The rare earth magnet powder having a further excellent magnetic anisotropy and thermal stability obtained by the production method of the present invention is a rare earth magnet having excellent magnetic anisotropy and thermal stability by being bonded with an organic binder or a metal binder. A magnet can be manufactured, and further, this rare earth magnet powder is molded to produce a green compact, and the green compact is magnetically anisotropic by hot pressing or hot isostatic pressing at a temperature of 600 to 900 ° C. Rare earth magnets excellent in heat resistance and thermal stability can be manufactured.
(C) Reasons for limiting the production conditions in the method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability described in (12), (13), (14), (15) or (16):
The hydrogen-absorbing rare earth magnet alloy raw material powder is heated to a predetermined temperature from room temperature to less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, or heated to less than 500 ° C. It is produced by performing a hydrogen absorption treatment for absorbing hydrogen by maintaining it at a predetermined temperature (for example, 100 ° C.). This rare earth magnet alloy raw material is heated to a predetermined temperature from room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, or a hydrogen absorption process for increasing the temperature is a conventional process. However, the reason for producing a hydrogen-absorbing rare earth magnet alloy raw material powder by pulverizing the hydrogen-absorbed rare earth magnet alloy raw material in this invention is as follows:
The bulk rare earth magnet alloy raw material treated with hydrogen absorption is easy to grind,
Hydrogen absorption treatment is easier to pulverize than other steps that are kept at high temperature because the temperature is treated at a relatively low temperature of less than 500 ° C.,
Since the massive rare earth magnet alloy raw material is pulverized to the same average particle diameter as that of the rare earth magnet powder in advance after the hydrogen absorption treatment, a sufficiently fine rare earth magnet powder can be obtained simply by crushing in the final pulverization step. The magnetic anisotropy is further improved from the fact that the rare earth magnet powder obtained is very rarely oxidized and the internal stress is very little accumulated.
This is because when the HDDR treatment is performed after hydrogen pulverization, the surface irregularities of the magnet powder are reduced to a smooth surface, and the thermal stability is improved because the specific surface area is reduced.

  The reason for pulverizing the rare earth magnet alloy raw material to the range of the average powder particle size: 10 to 1000 μm (more preferably 50 to 400 μm) after the hydrogen absorption treatment in producing the hydrogen absorbing rare earth magnet alloy raw material The rare earth magnet alloy raw material is relatively difficult to oxidize, but if it is intended to be finely pulverized to an average particle size of less than 10 μm, it is inevitable that it will be oxidized at the time of pulverization because it is fine. Since the coercive force of the rare earth magnet powder to be obtained is lowered, it is not preferable. On the other hand, when the average particle size is larger than 1000 μm, the easy magnetization axes in one powder particle of the rare earth magnet powder finally obtained by crushing are aligned. This is because it becomes difficult and magnetic anisotropy decreases, which is not preferable. The average particle diameter of the hydrogen-absorbing rare earth magnet alloy raw material powder is almost the same as that of the finally obtained rare earth magnet powder.

  To this hydrogen-absorbing rare earth magnet alloy raw material powder, 0.01 to 5 mol of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm is added. % To prepare a hydrogen-containing raw material mixed powder, and this hydrogen-containing raw material mixed powder is heated to a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and held. The hydrogen-containing raw material mixed powder is further subjected to hydrogen absorption / decomposition treatment for absorbing and decomposing hydrogen, and then maintained in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less. When a dehydrogenation treatment is performed to forcibly release hydrogen to promote phase transformation, followed by cooling and pulverization, a rare earth magnet powder with better magnetic anisotropy and thermal stability can be obtained. That.

  A hydrogen-containing raw material mixed powder obtained by adding and mixing Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder to the hydrogen-absorbing rare earth magnet alloy raw material powder is further mixed with hydrogen. When the absorption / decomposition treatment is performed and then the dehydrogenation treatment is performed, a rare earth magnet powder having more excellent magnetic anisotropy and thermal stability can be obtained for the following reason.

  Recent research has revealed that the reaction at the stage of hydrogen absorption / decomposition is important for anisotropy of rare earth magnet powder by HDDR treatment. On the other hand, if one or two of Dy or Tb is added in a large amount in the rare earth magnet alloy so as to improve the coercive force in order to improve the thermal stability, the literature (Japanese Patent Laid-Open No. 9-165601) discloses. As is the case, the anisotropy decreases, and a sufficient energy product cannot be obtained. This is because when the rare earth magnet alloy contains one or two of Dy or Tb in a large amount, the reaction of the hydrogen absorption / decomposition treatment described above is affected, and it is formed by the hydrogen absorption / decomposition reaction. It seems that this is because the state does not satisfy the anisotropy condition.

However, it was obtained by adding and mixing Dy hydride powder, Tb hydride powder or hydride powder of Dy-Tb binary alloy to the rare earth magnet alloy raw material powder treated with hydrogen absorption as in the present invention. When the hydrogen-containing raw material mixed powder is further subjected to hydrogen absorption / decomposition treatment, the decomposition reaction at that time is caused by formation of rare earth element hydride from the rare earth magnet alloy, and the remainder is Fe or (Fe, Co), Fe _2. The same rare earth element Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder is involved in this decomposition reaction in order to proceed in the direction of decomposition into B-based phases. Therefore, only the rare earth magnet alloy raw material powder is decomposed and formed by hydrogen absorption / decomposition reaction as in the case where a large amount of one or two of Dy or Tb is added to the rare earth magnet alloy. State that is is not in a state that does not satisfy the anisotropic conditions.

Next, when dehydrogenation is performed from this state, a phase based on R hydride, Fe or (Fe, Co) and Fe ₂ B decomposed in the rare earth magnet alloy raw material powder reacts to produce R ₂ Fe ₁₄ B In addition, a Dy hydride powder, a Tb hydride powder or a hydride powder of a Dy-Tb binary alloy also releases one of Dy or Tb by releasing hydrogen. Since the two types of atoms diffuse throughout the surface of the rare earth magnet alloy raw material powder and subsequently diffuse toward the inside of the rare earth magnet alloy raw material powder, the phase based on R ₂ Fe ₁₄ B finally formed is Compared to the original rare earth magnet alloy raw material powder, the content of one or two kinds of Dy or Tb is increased, and the content of one or two kinds of Dy or Tb in the vicinity of the surface in the powder particles is contained in the powder particles. Heart of As a result, the coercive force is improved and the temperature coefficient of the coercive force is reduced, so that the thermal stability is improved. On the other hand, since the condition for anisotropy is satisfied at the stage of hydrogen absorption / decomposition reaction, anisotropy actually occurs by dehydrogenation, resulting in a large coercive force and anisotropy. It is considered that a rare earth magnet powder excellent in the above can be obtained.

  In the present invention, the hydrogen-absorbing rare earth magnet alloy raw material powder is supplied with Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder having an average particle size of 0.1 to 50 μm. A hydrogen-containing raw material mixed powder is prepared by adding and mixing 01 to 5 mol%, and the hydrogen-containing raw material mixed powder is further heated, and the pressure is within a range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment is performed to maintain the temperature at a predetermined temperature, and hydrogen is absorbed into the raw material by this hydrogen absorption / decomposition treatment to promote phase transformation and decomposition.

  The average particle size of the Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder added to the hydrogen-absorbing rare earth magnet alloy raw material powder in order to produce the hydrogen-containing raw material mixed powder is 0.00. The reason for limiting to 1-50 μm is that if the average particle size of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is less than 0.1 μm, the oxidation becomes severe and handling is very On the other hand, if the average particle diameter exceeds 50 μm, the phase of Dy, Tb or Dy-Tb binary alloy or the compound phase containing excessive amounts of these elements segregates in the rare earth magnet powder. Since they cannot diffuse uniformly, the average particle size of these hydride powders was set to 0.1 to 50 μm (more preferably 1 to 10 μm). Moreover, the reason for limiting the amount of addition to 0.01 to 5 mol% is that if it is less than 0.01 mol%, the effect of improving the coercive force is not sufficient, while if it exceeds 5 mol%, the anisotropy decreases. Therefore, it is not preferable because sufficient magnetic properties cannot be obtained. Therefore, the addition amount of the hydride powder of Dy, the hydride powder of Tb or the hydride powder of the Dy-Tb binary alloy is 0.01 to 5 mol% (more preferably 0.3 to 3 mol%). Determined.

  The pressure in the hydrogen absorption / decomposition treatment step: The condition of maintaining a predetermined temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere of 10 to 1000 kPa is a known condition. The explanation of the reason for limitation is omitted.

  After such hydrogen absorption / decomposition treatment, intermediate heat treatment is performed as necessary. This intermediate heat treatment is a step of promoting anisotropy at an appropriate speed by changing the atmosphere to an inert gas atmosphere by an inert gas flow. This intermediate heat treatment is performed under a condition of maintaining a predetermined temperature within a temperature range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa. If the pressure of the inert gas atmosphere in the intermediate heat treatment is less than 10 kPa, the anisotropy becomes too fast and causes a decrease in the coercive force. On the other hand, if it exceeds 1000 kPa, the anisotropy hardly progresses and the residual This is not preferable because it causes a decrease in magnetic flux density.

  After performing an intermediate heat treatment as necessary, a heat treatment in reduced-pressure hydrogen is further performed as necessary. This heat treatment in hydrogen under reduced pressure is performed by using a hydrogen-containing raw material mixed powder subjected to hydrogen absorption / decomposition treatment in a hydrogen atmosphere at an absolute pressure of less than 0.65 to 10 kPa (preferably 2 to 8 kPa) or a hydrogen partial pressure of 0.65 to 10 kPa. This is a step of heat-treating the hydrogen-containing raw material mixed powder while leaving a part of the hydrogen in the mixed gas atmosphere of less than (preferably 2 to 8 kPa) hydrogen and an inert gas. By performing the heat treatment in hydrogen under reduced pressure, the coercive force and the residual magnetic flux density can be further improved.

  If necessary, dehydrogenation is performed after intermediate heat treatment and heat treatment in hydrogen under reduced pressure. The dehydrogenation treatment is a treatment that forcibly releases hydrogen from the hydrogen-containing raw material mixed powder by maintaining a vacuum atmosphere at an ultimate pressure of 0.13 kPa or less, thereby promoting further phase transformation. The ultimate pressure is maintained in a vacuum atmosphere of 0.13 kPa or less because dehydrogenation is not sufficiently performed at an ultimate pressure exceeding 0.13 kPa.

The cooling performed after the dehydrogenation is performed by flowing an inert gas (Ar gas) to room temperature. After cooling, it is crushed into rare earth magnet powder. The rare earth magnet powder obtained by pulverization has very little residual internal stress, so that it does not need to be heat-treated. The rare earth magnet powder having a further excellent magnetic anisotropy and thermal stability obtained by the production method of the present invention is a rare earth magnet having excellent magnetic anisotropy and thermal stability by being bonded with an organic binder or a metal binder. A magnet can be manufactured, and further, this rare earth magnet powder is molded to produce a green compact, and the green compact is magnetically anisotropic by hot pressing or hot isostatic pressing at a temperature of 600 to 900 ° C. Rare earth magnets excellent in heat resistance and thermal stability can be manufactured.
Magnetic anisotropy and thermal stability according to (7), (8), (9), (10), (11), (12), (13), (14), (15) or (16) The rare earth magnet alloy raw material used in the method for producing a rare earth magnet powder having excellent properties may or may not contain one or two of Dy or Tb. Therefore, the rare earth magnet alloy raw material used in the method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability according to the present invention is the ordinary magnetic anisotropic HDDR magnet powder described in Patent Documents 1 and 2. It has the same component composition as the rare earth magnet alloy raw material used in manufacturing, and more specifically includes Y which may or may not be included in one or two of Dy or Tb. If the rare earth element is R ′,
R ′: 10 to 20%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition with the balance consisting of Fe and inevitable impurities,
R ′: 10 to 20%, B: 3 to 20%, M: 0.001 to 5%, a rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities,
R ′: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities, or R ′: 10 It is a rare earth magnet alloy raw material containing 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, and the balance being composed of Fe and inevitable impurities.

  A rare earth magnet having the component composition shown in Table 1 is melted using a high-frequency vacuum melting furnace, homogenized by casting the obtained molten metal and holding it in an Ar gas atmosphere at 1100 ° C. for 24 hours. Ingots a to o of alloy raw materials were manufactured. These ingots a to o were crushed in an Ar gas atmosphere to produce blocks of 10 mm or less.

実施例１
表１の鋳塊ａ〜ｅのブロックをＡｒガス雰囲気中で表２に示される平均粒径になるように粉砕処理して希土類磁石合金原料粉末を作製し、この希土類磁石合金原料粉末に、いずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表２に示される量だけ添加し混合して混合粉末を作製し、この混合粉末に表２に示される条件で水素吸収処理を施し、引き続いて表２に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２に示される条件で中間熱処理を行い、さらに必要に応じて表２に示される条件で減圧水素中熱処理を行い、次いで表３に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより本発明法１〜５を実施した。
従来例1
表１の鋳塊ａ〜ｅのブロックを粉砕処理することなくまた水素化物粉末を添加して混合粉末を作ることなく表２に示される実施例１と同じ条件で水素吸収処理を施したのち、表２に示される実施例１と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２に示される条件で減圧水素中熱処理を行った後、Ａｒガス中で強制的に室温まで冷却し、表３に示される平均粒径になるように粉砕処理して希土類磁石原料水素化物粉末を作製したのち、この希土類磁石原料水素化物粉末にいずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表３に示される量だけ添加し混合して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に真空中で昇温して表３に示される条件に保持して拡散熱処理を施し、さらに表３に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して従来法１〜５を実施することにより希土類磁石粉末を製造した。

Example 1
The blocks of the ingots a to e in Table 1 are pulverized in an Ar gas atmosphere so as to have an average particle size shown in Table 2 to produce a rare earth magnet alloy raw material powder. The average particle size: 5 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in the amount shown in Table 2 and mixed to produce a mixed powder. The mixed powder is subjected to hydrogen absorption treatment under the conditions shown in Table 2, followed by hydrogen absorption / decomposition treatment under the conditions shown in Table 2, and subsequently subjected to intermediate heat treatment under the conditions shown in Table 2 as necessary. Further, if necessary, heat treatment in hydrogen under reduced pressure is performed under the conditions shown in Table 2, followed by dehydrogenation treatment under the conditions shown in Table 3, and then forcedly cooled to room temperature with Ar gas to 300 μm or less. Crush to produce rare earth magnet powder The present invention methods 1 to 5 were carried out.
Conventional example 1
After subjecting the blocks of ingots a to e in Table 1 to hydrogen absorption treatment under the same conditions as in Example 1 shown in Table 2 without pulverizing treatment and without adding hydride powder to make mixed powder, A hydrogen absorption / decomposition treatment was performed under the same conditions as in Example 1 shown in Table 2, followed by a heat treatment in reduced-pressure hydrogen under the conditions shown in Table 2 as necessary, and then forcibly at room temperature in Ar gas. The rare earth magnet raw material hydride powder was prepared by cooling to a mean particle size as shown in Table 3 and producing a rare earth magnet raw material hydride powder. Hydrogenated powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added in the amount shown in Table 3 and mixed to produce a hydrogen-containing raw material mixed powder. As shown in Table 3 After carrying out diffusion heat treatment while maintaining the conditions, and further performing dehydrogenation treatment under the conditions shown in Table 3, it was forcibly cooled to room temperature with Ar gas and crushed to 300 μm or less. Rare earth magnet powder was manufactured by carrying out.

  Electron beam microanalyzer (manufactured by JEOL Ltd.) which is one of wavelength dispersive X-ray spectrometers by embedding rare earth magnet powders obtained by the present invention methods 1 to 5 and conventional methods 1 to 5 in a phenol resin and polishing the mirror surface. The depth and surface coating of the Dy-Tb rich layer from the surface by measuring the detected intensity of Dy and / or Tb near the center and the surface analyzed by JXA-8800RL (hereinafter referred to as EPMA) and the intensity ratio thereof The rate value was determined and the results are shown in Table 4.

Further, the rare earth magnet powders obtained by the present invention methods 1 to 5 and the conventional methods 1 to 5 were each mixed with 3% by mass of an epoxy resin, kneaded, and compression-molded in a magnetic field of 1.6 MA / m. The green compact was heat-cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm ³ , and the magnetic properties of the obtained bonded magnet were measured. Table 5 shows. Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 5. Here, the temperature coefficient α _iHc of coercive force is α _iHc (% / ° C.) = {( _{Coercivity at} 150 ° C.−coercivity at room temperature (20 ° C.)) / Coercivity at room temperature (20 ° C.)} / (150 −20) A value obtained by × 100.

Further, the rare earth magnet powders obtained by the present invention methods 1 to 5 and the conventional methods 1 to 5 are compression molded in a magnetic field to produce an anisotropic green compact, and this anisotropic green compact is hot-pressed. In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa so that the direction of magnetic field application is the compression direction Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 5 shows the magnetic characteristics of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 5.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 1 to 5 and the conventional methods 1 to 5, and the outside was applied while applying a magnetic field of 1.6 MA / m in the compression direction. It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ cylindrical bonded magnets were produced, and the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, and then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, and heat after 1000 hours. The demagnetization factor was measured, and the results are shown in Table 5 to evaluate the thermal stability.

  Here, the thermal demagnetization factor is a value obtained by the following equation: thermal demagnetization factor (%) = {(total magnetic flux after exposure for a predetermined time−total magnetic flux before exposure) / total magnetic flux before exposure} × 100.

表１〜表５に示される結果から、Ａｒガス雰囲気中で粉砕処理し、これに水素化物粉末を添加して混合粉末を作る本発明法１〜５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、粉砕処理せずまた水素化物を添加しない従来法１〜５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かり、また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。

From the results shown in Tables 1 to 5, the bond made of the rare earth magnet powder obtained by the present invention methods 1 to 5 which was pulverized in an Ar gas atmosphere and added with hydride powder to make a mixed powder. The magnetic properties of magnets and hot-pressed magnets are compared with the magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by conventional methods 1 to 5 that are not pulverized and do not add hydride. It can be seen that both the residual magnetic flux density is improved and that the temperature coefficient of the coercive force is small and the thermal demagnetization factor is small, so that the thermal stability is also excellent.

  By using the rare earth magnet powder obtained by Method 1 of the present invention, the value of the depth from the surface of the Dy-Tb rich layer and the surface coverage ratio are determined by measuring the detected intensity and the intensity ratio of the present invention. This will be described in detail.

  First, the rare earth magnet powder obtained by the method 1 of the present invention was embedded in a phenol resin, polished on a mirror surface, and the element distribution of Dy in the internal cross section of the powder was observed by EPMA. An elemental distribution photograph of Dy taken at that time is shown in FIG. The more bright spots, the higher the Dy content. The more bright spots near the outer periphery of the cross section, the higher the Dy content near the surface of the powder particles than the center. Has been. Therefore, a line analysis of Dy on a straight line from point A to point B in FIG. The measurement conditions at this time are an acceleration voltage of 15 kV, a minimum electron beam diameter, a holding time of 1.0 sec / point, a measurement interval of 1.0 μm, and measurement using Dy characteristic X-rays / DyLα rays (wavelength: 0.1909 nm). went. The result is shown in FIG. The horizontal axis of the graph indicates the moving distance (mm) of the sample, and the vertical axis indicates the detection intensity of the DyLα ray in terms of the number of counts. DyLα rays of 800 counts or more are detected in portions corresponding to powder particles from about 0.01 mm to about 0.135 mm, and in particular, a peak near 0.01 mm (hereinafter referred to as peak A) is 1440 counts, 0.135 mm. A peak near the peak (hereinafter referred to as peak B) is 1380counts, and strong peaks are observed at both ends, and it can be seen that the content of Dy near the surface in the powder particles is larger than that near the center. Accordingly, when the strength near the center was determined as an average strength between 0.051 mm and 0.093 mm corresponding to 1/3 of the powder particle size, it was 811counts. Therefore, it was found that the intensity ratio of the peak A to the vicinity of the center was 1.78, and the peak B was 1.70, which was sufficiently larger than 1.2. In addition, when the same line analysis was performed 10 times while changing the direction of the sample, the detected intensity near the surface of 19 locations was 1.2 times or more that near the center, and a region with a higher Dy content covering the surface than this The ratio was 95%. Next, a line analysis was performed with the retention time of 1.0 sec and the measurement interval of 20 nm as fine as possible centering on the peak A. The result is shown in FIG. When the area of 1.2 times (973counts) or more, which seems to be sufficiently significant for the detection intensity near the center, was determined as the peak A area, the width was 4.1 μm.

  The magnetic powder of the conventional method 1 was similarly analyzed by EPMA. The results of line analysis at 1.0 μm intervals are shown in FIG. The average detected intensity of the DyLα ray near the center is 1176 counts, the intensity near the surface is 1360 counts near 0.02 mm (hereinafter referred to as peak C), and does not reach 1411 counts, which is 1.2 times the center. Moreover, the result of the line analysis of a 20 nm space | interval is shown in FIG. It was found that the intensity of peak C was not changed from 1180counts near the center by measurement at intervals of 20 nm, and there was almost no difference in the Dy content near the surface and near the center.

Similarly, the detected intensity of Dy + Tb near the center and near the surface analyzed by EPMA for the rare earth magnet powders produced by the present invention methods 2 to 5 and the conventional methods 2 to 5, the intensity ratio, the thickness of the Dy-Tb rich layer, The value of the surface coverage of the Dy-Tb rich layer was determined, and the rare earth magnet powders prepared by the inventive methods 6-30 and conventional methods 6-30 of Examples 2 to 6 described below were determined in the same manner. It was.
Example 2
The blocks of the ingots f to j in Table 1 were pulverized in an Ar gas atmosphere so as to have an average particle size shown in Table 6 to prepare a rare earth magnet alloy raw material powder. The average particle size: 5 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in the amount shown in Table 6 and mixed to produce a mixed powder. The mixed powder is subjected to hydrogen absorption treatment under the conditions shown in Table 6, subsequently subjected to hydrogen absorption / decomposition treatment under the conditions shown in Table 6, and subsequently subjected to intermediate heat treatment under the conditions shown in Table 7 as necessary. Further, if necessary, heat treatment in hydrogen under reduced pressure is performed under the conditions shown in Table 7, followed by dehydrogenation treatment under the conditions shown in Table 8, and then forcedly cooled to room temperature with Ar gas to 300 μm or less. Crush to produce rare earth magnet powder The present invention methods 6 to 10 were carried out.
Conventional example 2
A table after performing hydrogen absorption treatment under the same conditions as in Example 2 shown in Table 6 without pulverizing the blocks of ingots f to j in Table 1 and without adding hydride powder to make a mixed powder. 6 was subjected to hydrogen absorption / decomposition under the same conditions as in Example 2 and subsequently subjected to heat treatment in reduced-pressure hydrogen under the conditions shown in Table 7 as necessary, and then forcibly brought to room temperature in Ar gas. After cooling, the rare earth magnet raw material hydride powder was prepared by pulverizing to the average particle size shown in Table 8, and then all of the rare earth magnet raw material hydride powder had a Dy hydride having an average particle diameter of 5 μm. Powder, Tb hydride powder or hydride powder of Dy-Tb binary alloy is added in the amount shown in Table 8 and mixed to produce a hydrogen-containing raw material mixed powder. As shown in Table 8 After carrying out a diffusion heat treatment while maintaining the conditions, and further performing a dehydrogenation treatment under the conditions shown in Table 8, it is forcibly cooled to room temperature with Ar gas and crushed to 300 μm or less to produce a rare earth magnet powder. Thus, the conventional methods 6 to 10 were carried out.

  The rare earth magnet powders obtained by the present invention methods 6 to 10 and the conventional methods 6 to 10 were embedded in a phenol resin, polished on a mirror surface and analyzed by EPMA, and the detected intensity of Dy and / or Tb near the center and near the surface and its By measuring the intensity ratio, the depth from the surface of the Dy-Tb rich layer and the value of the surface coverage were determined, and the results are shown in Table 9.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 6 to 10 and the conventional methods 6 to 10, and the mixture was compressed and molded in a magnetic field of 1.6 MA / m. The green compact was heat-cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm ^3. The magnetic properties of the obtained bonded magnet were measured. Table 10 shows. Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 10.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 6 to 10 and the conventional methods 6 to 10 and kneaded, and while applying a magnetic field of 1.6 MA / m in the compression direction, It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ cylindrical bonded magnets were produced, and the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, and then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, and heat after 1000 hours. The demagnetization factor was measured, and the results are shown in Table 10 to evaluate the thermal stability.

Further, the rare earth magnet powder obtained by the present invention methods 6 to 10 and the conventional methods 6 to 10 is compression molded in a magnetic field to produce an anisotropic green compact, and this anisotropic green compact is hot-pressed. In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa so that the direction of magnetic field application is the compression direction Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 10 shows the magnetic characteristics of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 10.

表１および表６〜表１０に示される結果から、Ａｒガス雰囲気中で粉砕処理し、これに水素化物粉末を添加して混合粉末を作る本発明法６〜１０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、粉砕処理せずまた水素化物を添加しない従来法６〜１０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かる。また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
実施例３
表１の鋳塊ｋ〜ｏのブロックを表１１に示される平均粒径になるようにＡｒガス雰囲気中で粉砕処理して希土類磁石合金原料粉末を作製し、この希土類磁石合金原料粉末に、いずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表１１に示される量だけ添加し混合して混合粉末を作製し、この混合粉末に表１１に示される条件で水素吸収処理を施し、引き続いて表１１に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表１１に示される条件で中間熱処理を行い、さらに必要に応じて表１１に示される条件で減圧水素中熱処理を行い、次いで表１２に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより本発明法１１〜１５を実施した。
従来例３
表１の鋳塊ｋ〜ｏのブロックを粉砕処理することなくまた水素化物粉末を添加して混合粉末を作ることなく表１１に示される実施例３と同じ条件で水素吸収処理を施した後、表１１に示される実施例３と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて表１１に示される条件で減圧水素中熱処理を行った後、Ａｒガス中で強制的に室温まで冷却し、表１２に示される平均粒径になるように粉砕処理して希土類磁石原料水素化物粉末を作製したのち、この希土類磁石原料水素化物粉末にいずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表１２に示される量だけ添加し混合して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に真空中で昇温して表１２に示される条件に保持して拡散熱処理を施し、さらに表１２に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより従来法１１〜１５を実施した。

From the results shown in Table 1 and Tables 6 to 10, the rare earth magnet powders obtained by the present invention methods 6 to 10 were pulverized in an Ar gas atmosphere and added with hydride powder to make a mixed powder. The magnetic properties of the produced bonded magnet and hot-pressed magnet are compared with the magnetic properties of the bonded magnet and hot-pressed magnet produced by the rare-earth magnet powder obtained by the conventional methods 6 to 10 which are not pulverized and do not add hydride. It can be seen that both the coercive force and the residual magnetic flux density are improved. Further, it can be seen that since the temperature coefficient of the coercive force is small and the thermal demagnetization factor is small, the thermal stability is also excellent.
Example 3
The blocks of the ingots k to o in Table 1 were pulverized in an Ar gas atmosphere so as to have an average particle size shown in Table 11 to produce a rare earth magnet alloy raw material powder. The average particle size: 5 μm Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder was added in the amount shown in Table 11 and mixed to produce a mixed powder. The mixed powder is subjected to hydrogen absorption treatment under the conditions shown in Table 11, subsequently subjected to hydrogen absorption / decomposition treatment under the conditions shown in Table 11, and subsequently subjected to intermediate heat treatment under the conditions shown in Table 11 as necessary. Further, if necessary, heat treatment in reduced-pressure hydrogen is performed under the conditions shown in Table 11, and then dehydrogenation treatment is performed under the conditions shown in Table 12, followed by forced cooling to room temperature with Ar gas to 300 μm or less. Crush to rare earth Inventive methods 11 to 15 were carried out by producing similar magnet powders.
Conventional example 3
After performing the hydrogen absorption treatment under the same conditions as in Example 3 shown in Table 11 without crushing the blocks of ingots k to o in Table 1 and without adding hydride powder to make a mixed powder, After performing hydrogen absorption / decomposition treatment under the same conditions as in Example 3 shown in Table 11 and subsequently performing heat treatment in hydrogen under reduced pressure under the conditions shown in Table 11 as necessary, it is forced to room temperature in Ar gas. The rare earth magnet raw material hydride powder was prepared by pulverizing to the average particle size shown in Table 12 to produce a rare earth magnet raw material hydride powder. Hydrogenated powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added in the amount shown in Table 12 and mixed to produce a hydrogen-containing raw material mixed powder. Raise the temperature in Table 1 After performing diffusion heat treatment under the conditions shown in FIG. 12 and further performing dehydrogenation treatment under the conditions shown in Table 12, it is forcibly cooled to room temperature with Ar gas, and pulverized to 300 μm or less. Conventional methods 11 to 15 were carried out by manufacturing

  The rare earth magnet powders obtained by the present invention methods 11 to 15 and the conventional methods 11 to 15 were embedded in phenol resin, polished on a mirror surface and analyzed by EPMA, and the detected intensity of Dy and / or Tb near the center and near the surface and By measuring the intensity ratio, the depth from the surface of the Dy-Tb rich layer and the value of the surface coverage were determined. The results are shown in Table 13.

The rare earth magnet powders obtained by the present invention methods 11 to 15 and the conventional methods 11 to 15 were each mixed with 3% by mass of an epoxy resin and kneaded and compression molded in a magnetic field of 1.6 MA / m to obtain a green compact. The green compact was heat-cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm ^3. The magnetic properties of the obtained bonded magnet are shown in Table 14. It was shown to. Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 14.

In addition, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 11 to 15 and the conventional methods 11 to 15, and the outside was applied while applying a magnetic field of 1.6 MA / m in the compression direction. It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ cylindrical bonded magnets were produced, and the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, and then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, and heat after 1000 hours. The demagnetization factor was measured, and the results are shown in Table 14 to evaluate the thermal stability.

Further, the rare earth magnet powder obtained by the present invention methods 11 to 15 and the conventional methods 11 to 15 is produced in an anisotropic magnetic powder in a magnetic field, and the anisotropic green compact is set in a hot press apparatus. In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa so that the direction of magnetic field application is the compression direction Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 14 shows the magnetic characteristics of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 14.

表１および表１１〜表１４に示される結果から、Ａｒガス雰囲気中で粉砕処理し、これに水素化物粉末を添加して混合粉末を作る本発明法１１〜１５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、粉砕処理せずまた水素化物を添加しない従来法１１〜１５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かる。また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
実施例４
表１の鋳塊ａ〜ｅのブロックに表１５に示される条件の水素吸収処理を施した後、この水素吸収処理したブロックを表１５に示される平均粒径になるように粉砕処理して水素吸収希土類磁石合金原料粉末を作製し、この水素吸収希土類磁石合金原料粉末に、いずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表１５に示される量だけ添加し混合して水素含有原料混合粉末を作製し、
引き続いて表１５に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表１５に示される条件で中間熱処理を行い、さらに必要に応じて表１５に示される条件で減圧水素中熱処理を行い、さらに表１６に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより本発明法１６〜２０を実施した。
従来例４
表１の鋳塊ａ〜ｅのブロックを表１５に示される条件の水素吸収処理を施した後、粉砕処理することなくまた水素化物粉末を添加して水素含有原料混合粉末を作ることなく表１５に示される実施例４と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて表１５に示される条件で減圧水素中熱処理を行った後、Ａｒガス中で強制的に室温まで冷却し、表１６に示される平均粒径になるように粉砕処理して希土類磁石原料水素化物粉末を作製し、この希土類磁石原料水素化物粉末にいずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表１６に示される量だけ添加し混合して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に真空中で昇温して表１６に示される条件に保持して拡散熱処理を施し、さらに表１６に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより従来法１６〜２０を実施した。

From the results shown in Table 1 and Tables 11 to 14, the rare earth magnet powders obtained by the present invention methods 11 to 15 were pulverized in an Ar gas atmosphere and hydride powder was added thereto to produce mixed powders. The magnetic properties of the produced bonded magnet and hot-pressed magnet are compared with the magnetic properties of the bonded magnet and hot-pressed magnet produced by the rare earth magnet powder obtained by the conventional methods 11 to 15 which are not pulverized and do not add hydride. It can be seen that both the coercive force and the residual magnetic flux density are improved. Further, it can be seen that since the temperature coefficient of the coercive force is small and the thermal demagnetization factor is small, the thermal stability is also excellent.
Example 4
After the blocks of ingots a to e in Table 1 were subjected to hydrogen absorption treatment under the conditions shown in Table 15, the hydrogen-absorbed blocks were pulverized so as to have an average particle size shown in Table 15 to generate hydrogen. Absorbing rare earth magnet alloy raw material powder was prepared, and all of the hydrogen absorbing rare earth magnet alloy raw material powder were Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride having an average particle size of 5 μm. Add the amount of powder shown in Table 15 and mix to make a hydrogen-containing raw material mixed powder,
Subsequently, hydrogen absorption / decomposition treatment is performed under the conditions shown in Table 15, followed by intermediate heat treatment under the conditions shown in Table 15 as necessary, and further under reduced pressure hydrogen under the conditions shown in Table 15 as necessary. After heat treatment and further dehydrogenation treatment under the conditions shown in Table 16, the method of the present invention 16 is produced by forcibly cooling to room temperature with Ar gas and crushing to 300 μm or less to produce rare earth magnet powder. ~ 20 were carried out.
Conventional example 4
After the blocks of the ingots a to e in Table 1 were subjected to the hydrogen absorption treatment under the conditions shown in Table 15, the hydride powder was not added and the hydrogen-containing raw material mixed powder was not produced without pulverizing treatment. Hydrogen absorption / decomposition treatment is performed under the same conditions as in Example 4 shown in the following, followed by heat treatment in reduced-pressure hydrogen under the conditions shown in Table 15 as necessary, followed by forced cooling to room temperature in Ar gas Then, the rare earth magnet raw material hydride powder was pulverized so as to have an average particle size shown in Table 16, and both of the rare earth magnet raw material hydride powders had a Dy hydride powder with an average particle diameter of 5 μm, A hydride powder of Tb or a hydride powder of a Dy-Tb binary alloy is added in an amount shown in Table 16 and mixed to prepare a hydrogen-containing raw material mixed powder. The hydrogen-containing raw material mixed powder is heated in vacuum. Shown in Table 16 The material is subjected to diffusion heat treatment under the conditions shown in Table 16, and further subjected to dehydrogenation treatment under the conditions shown in Table 16, and then forcedly cooled to room temperature with Ar gas and pulverized to 300 μm or less to produce rare earth magnet powder. Thus, conventional methods 16 to 20 were carried out.

  The rare earth magnet powder obtained by the present invention method 16-20 and the conventional method 16-20 was embedded in phenol resin, polished on a mirror surface and analyzed by EPMA, and the detected intensity of Dy and / or Tb near the center and near the surface and its By measuring the intensity ratio, the depth from the surface of the Dy-Tb rich layer and the value of the surface coverage were determined, and the results are shown in Table 17.

  As an example, a photograph of the elemental distribution of Dy taken when the rare earth magnet powder obtained by the method 16 of the present invention was embedded in a phenolic resin, polished on a mirror surface, and observed for the elemental distribution of Dy in the internal cross section of the powder by EPMA is shown in FIG. Shown in Since there are many bright spots near the outer periphery of the cross section, it is indicated that the Dy content is higher in the vicinity of the surface in the powder particles than in the vicinity of the center. FIG. 7 shows the result of the actual line analysis of Dy on the straight line from point E to point F in FIG. According to FIG. 7, strong peaks are observed at both ends, and it can be seen that the content of Dy near the surface in the powder particles is higher than that near the center. The average detected intensity of the peaks at both ends was 1412 counts, the average detected intensity in the range of 1/3 of the powder particle size near the center was 915 counts, and the intensity ratio with respect to the vicinity of the center was 1.54. The surface coverage was 95% as a result of performing the same line analysis 10 times while changing the direction of the sample. Further, as a result of scanning the peaks at both ends at a fine interval, the width of the region that is 1.2 times or more the detection intensity near the center is 4.5 μm.

  The values in Table 17 are obtained from the measurement results of the rare earth magnet powders obtained by the present invention method 16 and the rare earth magnet powders obtained by the present invention methods 17 to 20 and the conventional methods 16 to 20 in the same manner. Value.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention method 16-20 and the conventional method 16-20, and compression molded in a magnetic field of 1.6 MA / m. The green compact was heat-cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm ³ , and the magnetic properties of the obtained bonded magnet were measured. It is shown in Table 18. Further, the temperature coefficient α _iHc of the coercive force was determined from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 18. Here, the temperature coefficient α _iHc of coercive force is α _iHc (% / ° C.) = {( _{Coercivity at} 150 ° C.−coercivity at room temperature (20 ° C.)) / Coercivity at room temperature (20 ° C.)} / (150 −20) A value obtained by × 100.

Further, the rare earth magnet powder obtained by the present invention method 16-20 and the conventional method 16-20 is compression-molded in a magnetic field to produce an anisotropic green compact. In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 18 shows the magnetic properties of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was determined from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 18.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention method 16-20 and the conventional method 16-20, and the outside was applied while applying a magnetic field of 1.6 MA / m in the compression direction. It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ columnar bonded magnets were prepared, and the magnetic properties of the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, and 1000 hours. The thermal demagnetization rate was measured later, and the results are shown in Table 18 to evaluate the thermal stability.

  Here, the thermal demagnetization factor is a value obtained by the following equation: thermal demagnetization factor (%) = {(total magnetic flux after exposure for a predetermined time−total magnetic flux before exposure) / total magnetic flux before exposure} × 100.

表１および表１５〜表１８に示される結果から、水素吸収希土類磁石原料粉末に水素化物粉末を添加して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に水素吸収・分解処理を施す本発明法１６〜２０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施したのち水素吸収・分解処理を施して得られた希土類磁石原料水素化物粉末に水素化物粉末を添加して得られた水素含有原料混合粉末を拡散熱処理する従来法１６〜２０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かり、また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
実施例５
表１の鋳塊ｆ〜ｊのブロックに表１９に示される条件の水素吸収処理を施し、この水素吸収処理したブロックを表１９に示される平均粒径になるように粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、この水素吸収処理した希土類磁石合金原料粉末に、いずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表１９に示される量だけ添加し混合して水素含有原料混合粉末を作製し、
引き続いて表１９に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表１９に示される条件で中間熱処理を行い、さらに必要に応じて表２０に示される条件で減圧水素中熱処理を行い、さらに表２０に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより本発明法２１〜２５を実施した。
従来例５
表１の鋳塊ｆ〜ｊのブロックを表１９に示される実施例５同じ条件の水素吸収処理を施した後、表１９に示される実施例５と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２０に示される条件で減圧水素中熱処理を行ったのち、Ａｒガス中で強制的に室温まで冷却し、表２０に示される平均粒径になるように粉砕処理して希土類磁石原料水素化物粉末を作製したのち、この希土類磁石原料水素化物粉末にいずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表２０に示される量だけ添加し混合して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に真空中で昇温して表２０に示される条件に保持して拡散熱処理を施し、さらに表２０に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより従来法２１〜２５を実施した。

From the results shown in Table 1 and Tables 15 to 18, hydride powder is added to the hydrogen-absorbing rare earth magnet raw material powder to produce a hydrogen-containing raw material mixed powder, and this hydrogen-containing raw material mixed powder is subjected to hydrogen absorption / decomposition treatment. The magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by the present invention method 16 to 20 are as follows. Hydrogen raw material hydrogen obtained after hydrogen absorption treatment and hydrogen absorption / decomposition treatment Compared to the magnetic properties of bonded magnets and hot-pressed magnets made with rare earth magnet powders obtained by conventional methods 16-20, wherein the hydrogen-containing raw material mixed powder obtained by adding hydride powder to the halide powder is subjected to diffusion heat treatment, It can be seen that both the coercive force and the residual magnetic flux density are improved, the temperature coefficient of the coercive force is small, and the thermal demagnetization factor is small. It can be seen that are also excellent.
Example 5
The blocks of ingots f to j in Table 1 are subjected to hydrogen absorption treatment under the conditions shown in Table 19, and the blocks subjected to the hydrogen absorption treatment are pulverized so as to have an average particle size shown in Table 19 to be subjected to hydrogen absorption treatment. The rare earth magnet alloy raw material powder was prepared, and the hydrogen-absorbed rare earth magnet alloy raw material powder was made of any of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy having an average particle size of 5 μm. Add hydride powder in the amount shown in Table 19 and mix to make hydrogen-containing raw material mixed powder,
Subsequently, hydrogen absorption / decomposition treatment was performed under the conditions shown in Table 19, followed by intermediate heat treatment under the conditions shown in Table 19 as necessary, and further under reduced pressure hydrogen under the conditions shown in Table 20 as necessary. After heat treatment and further dehydrogenation treatment under the conditions shown in Table 20, the method of the present invention 21 is produced by forcibly cooling to room temperature with Ar gas and pulverizing to 300 μm or less to produce rare earth magnet powder. ~ 25 were carried out.
Conventional Example 5
After the blocks of the ingots f to j in Table 1 were subjected to hydrogen absorption treatment under the same conditions as in Example 5 shown in Table 19, they were subjected to hydrogen absorption / decomposition treatment under the same conditions as in Example 5 shown in Table 19, Subsequently, after performing heat treatment in reduced pressure hydrogen under the conditions shown in Table 20 as necessary, forcibly cooled to room temperature in Ar gas, and pulverized to an average particle size shown in Table 20 After preparing the rare earth magnet raw material hydride powder, all of the rare earth magnet raw material hydride powder has an average particle size of 5 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder. Is added and mixed in the amount shown in Table 20 to prepare a hydrogen-containing raw material mixed powder, and the hydrogen-containing raw material mixed powder is heated in vacuum and kept under the conditions shown in Table 20 and subjected to diffusion heat treatment. Furthermore, the conditions shown in Table 20 In After performing dehydrogenation treatment, forced cooling to room temperature in an Ar gas, was carried out conventional methods 21 to 25 by producing a rare earth magnet powder and then disintegrated to 300μm or less.

  The rare earth magnet powders obtained by the present invention methods 21 to 25 and the conventional methods 21 to 25 are embedded in a phenol resin, polished on a mirror surface and analyzed by EPMA, and the detected intensity of Dy and / or Tb near the center and near the surface and its By measuring the intensity ratio, the depth from the surface of the Dy-Tb rich layer and the value of the surface coverage were determined, and the results are shown in Table 21.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 21 to 25 and the conventional methods 21 to 25, followed by compression molding in a magnetic field of 1.6 MA / m. The green compact was heat-cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm ^3. The magnetic properties of the obtained bonded magnet were measured. It is shown in Table 22. Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 22.

In addition, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention methods 21 to 25 and the conventional methods 21 to 25 and kneaded, and while applying a magnetic field of 1.6 MA / m in the compression direction It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ columnar bonded magnets were produced, and the magnetic properties of the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, 1000 hours. The thermal demagnetization factor after the lapse of time was measured, and the results are shown in Table 22 to evaluate the thermal stability.

Further, the rare earth magnet powders obtained by the present invention methods 21 to 25 and the conventional methods 21 to 25 are compression molded in a magnetic field to produce an anisotropic green compact. In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa so that the direction of magnetic field application is the compression direction Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 22 shows the magnetic characteristics of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 22.

表１および表１９〜２２に示される結果から、水素吸収希土類磁石原料粉末に水素化物粉末を添加して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に水素吸収・分解処理を施す本発明法２１〜２５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施したのち水素吸収・分解処理を施して得られた希土類磁石原料水素化物粉末に水素化物粉末を添加して得られた水素含有原料混合粉末を拡散熱処理する従来法２１〜２５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かり、また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
実施例６
表１の鋳塊ｋ〜ｏのブロックに表２３に示される条件の水素吸収処理を施し、この水素吸収処理したブロックを表２３に示される平均粒径になるように粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、この水素吸収処理した希土類磁石合金原料粉末に、いずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表２３に示される量だけ添加し混合して水素含有原料混合粉末を作製し、
引き続いて水素含有原料混合粉末に表２３に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２３に示される条件で中間熱処理を行い、さらに必要に応じて表２３に示される条件で減圧水素中熱処理を行い、さらに表２４に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより本発明法２６〜３０を実施した。
従来例６
表１の鋳塊ｋ〜ｏのブロックを表２３に示される実施例６同じ条件の水素吸収処理を施した後、粉砕処理することなくまた水素化物粉末を添加して水素含有原料混合粉末を作ることなく実施例６と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２３に示される条件で減圧水素中熱処理を行った後、Ａｒガス中で強制的に室温まで冷却し、表２４に示される平均粒径になるように粉砕処理して希土類磁石原料水素化物粉末を作製したのち、この希土類磁石原料水素化物粉末にいずれも平均粒径：５μｍのＤｙの水素化物粉末、Ｔｂの水素化物粉末またはＤｙ−Ｔｂ二元系合金の水素化物粉末を表２４に示される量だけ添加し混合して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に真空中で昇温して表２４に示される条件に保持して拡散熱処理を施し、さらに表２４に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に解砕して希土類磁石粉末を製造することにより従来法２６〜３０を実施した。

From the results shown in Table 1 and Tables 19-22, hydride powder is added to the hydrogen-absorbing rare earth magnet raw material powder to produce a hydrogen-containing raw material mixed powder, and this hydrogen-containing raw material mixed powder is subjected to hydrogen absorption / decomposition treatment. The magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by the inventive methods 21 to 25 are the rare earth magnet raw material hydrides obtained by hydrogen absorption / decomposition after hydrogen absorption. Compared to the magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by conventional methods 21 to 25, in which hydride powders obtained by adding hydride powders to powders are subjected to diffusion heat treatment. It can be seen that both the magnetic force and the residual magnetic flux density are improved, the temperature coefficient of the coercive force is small, and the thermal demagnetization factor is small. It can be seen that are better.
Example 6
The blocks of ingots k to o in Table 1 are subjected to hydrogen absorption treatment under the conditions shown in Table 23, and the hydrogen-absorbed treatment blocks are pulverized so as to have an average particle size as shown in Table 23. The rare earth magnet alloy raw material powder was prepared, and the hydrogen-absorbed rare earth magnet alloy raw material powder was made of any of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy having an average particle size of 5 μm. Add and mix hydride powder in the amount shown in Table 23 to produce a hydrogen-containing raw material mixed powder,
Subsequently, the hydrogen-containing raw material mixed powder was subjected to hydrogen absorption / decomposition treatment under the conditions shown in Table 23, followed by intermediate heat treatment under the conditions shown in Table 23 as necessary, and further as shown in Table 23 as necessary. Heat treatment in reduced-pressure hydrogen under the conditions described above, and further after dehydrogenation treatment under the conditions shown in Table 24, forcibly cooled to room temperature with Ar gas and pulverized to 300 μm or less to produce rare earth magnet powder Thus, the inventive methods 26 to 30 were carried out.
Conventional Example 6
After the blocks of the ingots k to o in Table 1 were subjected to hydrogen absorption treatment under the same conditions as in Example 6 shown in Table 23, hydride powder was added without pulverization to make a hydrogen-containing raw material mixed powder. Without being subjected to hydrogen absorption / decomposition treatment under the same conditions as in Example 6, followed by heat treatment in reduced pressure hydrogen under the conditions shown in Table 23 as necessary, and then forcedly cooled to room temperature in Ar gas. After pulverizing to prepare the rare earth magnet raw material hydride powder so as to have an average particle diameter shown in Table 24, each of the rare earth magnet raw material hydride powders has a Dy hydride powder having an average particle diameter of 5 μm, A hydride powder of Tb or a hydride powder of a Dy-Tb binary alloy is added in an amount shown in Table 24 and mixed to prepare a hydrogen-containing raw material mixed powder. Shown in Table 24 After the diffusion heat treatment is carried out under the conditions shown in Table 24, and after the dehydrogenation treatment is performed under the conditions shown in Table 24, it is forcibly cooled to room temperature with Ar gas and pulverized to 300 μm or less to produce rare earth magnet powder. Thus, conventional methods 26 to 30 were carried out.

  The rare earth magnet powder obtained by the present invention method 26-30 and the conventional method 26-30 is embedded in a phenol resin, polished on a mirror surface and analyzed by EPMA, and the detected intensity of Dy and / or Tb near the center and near the surface and its By measuring the intensity ratio, the depth from the surface of the Dy-Tb rich layer and the value of the surface coverage were determined, and the results are shown in Table 25.

3% by mass of epoxy resin is added to each of the rare earth magnet powders obtained by the present invention method 26-30 and the conventional methods 26-30 and kneaded and compression molded in a magnetic field of 1.6 MA / m to obtain a green compact. The green compact was then thermoset in an oven at 150 ° C. for 2 hours to produce a bond magnet having a density of 6.0 to 6.1 g / cm ^3. Table 26 shows the magnetic properties of the obtained bond magnet. It was shown to. Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 26.

Further, 3% by mass of an epoxy resin was added to each of the rare earth magnet powders obtained by the present invention method 26-30 and the conventional method 26-30 and kneaded, while applying a magnetic field of 1.6 MA / m in the compression direction. It is compression-molded into a cylindrical shape having a size of 10 mm in diameter and 7 mm in height, and then this cylindrical green compact is thermoset in an oven at 150 ° C. for 2 hours to obtain a density of 6.0 to 6.1 g / cm. ³ cylindrical bonded magnets were produced, and the magnetic properties of the obtained bonded magnets were magnetized with a pulse magnetic field of 70 kOe, and then left in an oven maintained at 100 ° C. for 1000 hours for 3 hours, 100 hours, 1000 hours. The thermal demagnetization factor after the lapse of time was measured, and the results are shown in Table 26 to evaluate the thermal stability.

Further, the rare earth magnet powder obtained by the present invention method 26-30 and the conventional method 26-30 was produced in an anisotropic magnetic powder in a magnetic field, and the anisotropic green compact was set in a hot press apparatus, In Ar gas, temperature: 750 ° C., pressure: 58.8 MPa so that the magnetic field application direction is the compression direction Hot pressing was performed under the condition of holding for 1 minute, followed by rapid cooling to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm ^3. Table 26 shows the magnetic characteristics of the obtained hot pressed magnet. . Further, the temperature coefficient α _iHc of the coercive force was obtained from the result of measuring the magnetic characteristics at 150 ° C., and the value is shown in Table 26.

表１および表２３〜２６に示される結果から、水素吸収希土類磁石原料粉末に水素化物粉末を添加して水素含有原料混合粉末を作製し、この水素含有原料混合粉末に水素吸収・分解処理を施す本発明法２６〜３０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施したのち水素吸収・分解処理を施して得られた希土類磁石原料水素化物粉末に水素化物粉末を添加して得られた水素含有原料混合粉末を拡散熱処理する従来法２６〜３０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、保磁力および残留磁束密度がともに向上していることが分かり、また保磁力の温度係数が小さく、さらに熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。

From the results shown in Table 1 and Tables 23 to 26, a hydride powder is added to the hydrogen-absorbing rare earth magnet raw material powder to produce a hydrogen-containing raw material mixed powder, and this hydrogen-containing raw material mixed powder is subjected to hydrogen absorption / decomposition treatment. The magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by the present invention method 26-30 are hydrides of rare earth magnet raw materials obtained by hydrogen absorption / decomposition after hydrogen absorption. Compared to the magnetic properties of bonded magnets and hot-pressed magnets made from rare earth magnet powders obtained by conventional methods 26-30, in which a hydrogen-containing raw material mixed powder obtained by adding hydride powder to the powder is subjected to diffusion heat treatment. It can be seen that both the magnetic force and the residual magnetic flux density are improved, the temperature coefficient of the coercive force is small, and the thermal demagnetization factor is small. It can be seen that are better.

It is an element distribution photograph by the electron beam microanalyzer (EMPA) which shows the element distribution of Dy contained in the anisotropic magnet powder produced by this invention method 1. FIG. It is a line-analysis graph by an electron beam microanalyzer (EMPA) which shows Dy distribution on the AB line in FIG. 1 of Dy contained in the anisotropic magnet powder produced by this invention method 1. FIG. FIG. 3 is a line analysis graph showing the element distribution on the straight line of Dy contained in the anisotropic magnet powder produced by the method 1 of the present invention, and scanning the vicinity of the peak A in FIG. 2 at fine intervals. It is a line analysis graph by an electron beam microanalyzer (EMPA) which shows element distribution of Dy contained in anisotropic magnet powder produced by conventional method 1. FIG. 5 is a line analysis graph obtained by scanning the vicinity of the peak C in FIG. 4 at a fine interval showing the element distribution of Dy contained in the anisotropic magnet powder produced by the conventional method 1. FIG. It is an element distribution photograph by the electron beam microanalyzer (EMPA) which shows element distribution of Dy contained in the anisotropic magnet powder produced by this invention method 16. FIG. It is a line analysis graph by an electron beam microanalyzer (EMPA) which shows Dy distribution on the EF straight line in FIG. 6 of Dy contained in the anisotropic magnet powder produced by this invention method 16. FIG.

Claims (20)

In atomic% (hereinafter,% indicates atomic%), R (wherein R represents one or more of rare earth elements including Y excluding Dy and Tb; the same shall apply hereinafter): 5 to 20 %, One or two of Dy and Tb is contained in an amount of 0.01 to 10%, B: 3 to 20%, the balance is composed of Fe and inevitable impurities, and the average powder particle size is 10 to 10%. A rare earth magnet powder having 1000 μm,
This rare earth magnet powder is covered with 70% or more of the entire surface with a layer having a thickness of 0.05 to 50 μm and a high content of one or two of Dy and Tb (hereinafter referred to as Dy-Tb rich layer). One or two concentrations of Dy and Tb in the Dy-Tb rich layer have a maximum detection intensity by the wavelength dispersion type X-ray spectroscopy of one or two of Dy and Tb. A rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by being 1.2 to 5 times the average detected intensity in the center within a range of 1/3. R: 5 to 20%, one or two of Dy and Tb are 0.01 to 10%, B is 3 to 20%, M (where M is Ga, Zr, Nb, Mo, Hf, Ta, W) , Ni, Al, Ti, V, Cu, Cr, Ge, C, and Si are included.): 0.001 to 5%, with the balance being Fe and inevitable impurities A rare earth magnet powder having a component composition and having an average powder particle size: 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and containing a large amount of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle by the maximum detection intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. A rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by being 1.2 to 5 times the average detected intensity of the central part in. R: 5 to 20%, Co: 0.1 to 50%, one or two of Dy and Tb are contained in an amount of 0.01 to 10%, B: 3 to 20%, the balance being Fe and inevitable impurities A rare earth magnet powder having a composition of components and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and containing a large amount of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle by the maximum detection intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. A rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by being 1.2 to 5 times the average detected intensity of the central part in. R: 5 to 20%, one or two of Dy and Tb 0.01 to 10%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5% A rare earth magnet powder having a component composition consisting of Fe and inevitable impurities and having an average powder particle size of 10 to 1000 μm,
This rare earth magnet powder is covered with a Dy-Tb rich layer having a thickness of 0.05 to 50 μm and containing a large amount of one or two of Dy and Tb at least 70% of the entire surface. The concentration of one or two of Dy and Tb in the Tb-rich layer is within the range of 1/3 of the particle size of the powder particle by the maximum detection intensity by one or two wavelength-dispersive X-ray spectroscopy of Dy and Tb. A rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by being 1.2 to 5 times the average detected intensity of the central part in. Recrystallized grains mainly composed of an R ₂ Fe ₁₄ B type intermetallic compound phase having a tetragonal crystal structure have recrystallized textures adjacent to each other. There are 50% by volume or more of recrystallized grains having a ratio (b / a) between the shortest grain size a and the longest grain size b of less than 2, and the average recrystallized grain size of the recrystallized grains 5. The magnetic anisotropy HDDR magnet powder having a basic structure of 0.05 to 5 μm in size is excellent in magnetic anisotropy and thermal stability according to claim 1, 2, 3 or 4 Rare earth magnet powder. 6. A rare earth magnet comprising the rare earth magnet powder having excellent magnetic anisotropy and thermal stability according to claim 1, 2, 3, 4, or 5 bonded with an organic binder or a metal binder. 6. A rare earth magnet obtained by hot pressing or hot isostatic pressing the rare earth magnet powder having excellent magnetic anisotropy and thermal stability according to claim 1, 2, 3, 4 or 5. The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average powder particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. 1 to 50 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added and mixed to make a mixed powder,
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average powder particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. 1 to 50 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added and mixed to make a mixed powder,
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, an intermediate heat treatment is performed by holding the mixed powder subjected to hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average powder particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. 1 to 50 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added and mixed to make a mixed powder,
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, the mixed powder that has been subjected to hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere of hydrogen and an inert gas, heat treatment in reduced pressure hydrogen is performed while leaving some hydrogen in the mixed powder,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. The rare earth magnet alloy raw material is pulverized in an inert gas atmosphere to an average powder particle size of 10 to 1000 μm to prepare a rare earth magnet alloy raw material powder. 1 to 50 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder is added and mixed to make a mixed powder,
The mixed powder was subjected to a hydrogen absorption treatment for absorbing hydrogen by raising the temperature from a room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, and then holding the temperature. : A hydrogen absorption / decomposition treatment in which hydrogen is absorbed into the mixed powder and decomposed by raising the temperature to a temperature within a range of 500 to 1000 ° C. and holding in a hydrogen gas atmosphere of 10 to 1000 kPa,
Subsequently, an intermediate heat treatment is performed by holding the mixed powder subjected to hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Subsequently, the mixed powder that has been subjected to the intermediate heat treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere with the active gas, a heat treatment in reduced-pressure hydrogen is performed while leaving some hydrogen in the mixed powder,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. The rare earth magnet alloy raw material according to claim 8, 9, 10 or 11 is a rare earth magnetic alloy raw material homogenized under a condition of holding at a temperature of 600 to 1200 ° C in a vacuum or an Ar gas atmosphere. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability. After the rare earth magnet alloy raw material is subjected to a hydrogen absorption treatment in which hydrogen is absorbed by raising the temperature from room temperature to a temperature of less than 500 ° C. or holding it after raising the temperature in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. An average powder particle size: A rare earth magnet alloy raw material powder (hereinafter referred to as a hydrogen absorbing rare earth magnet alloy raw material powder) that has been pulverized and hydrogen-absorbed to 10 to 1000 μm is prepared,
To this hydrogen-absorbing rare earth magnet alloy raw material powder, 0.01 to 5 μm of Dy hydride powder, Tb hydride powder or Dy-Tb binary alloy hydride powder with an average powder particle size of 0.1 to 50 μm was added. Mol% added and mixed to produce hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. 0.01-5 mol of hydrogen-absorbing rare earth magnet alloy raw material powder with an average powder particle size: 0.1-50 μm of Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder % To make a hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the hydrogen-containing raw material mixed powder subjected to the hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. 0.01-5 mol of hydrogen-absorbing rare earth magnet alloy raw material powder with an average powder particle size: 0.1-50 μm of Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder % To make a hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, the hydrogen-containing raw material mixed powder that has been subjected to hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of 0.65 to A heat treatment in reduced-pressure hydrogen is performed while leaving part of the hydrogen in the hydrogen-containing raw material mixed powder by maintaining in a mixed gas atmosphere of hydrogen and inert gas of less than 10 kPa,
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. 0.01-5 mol of hydrogen-absorbing rare earth magnet alloy raw material powder with an average powder particle size: 0.1-50 μm of Dy hydride powder, Tb hydride powder, or Dy-Tb binary alloy hydride powder % To make a hydrogen-containing raw material mixed powder,
The hydrogen-containing raw material mixed powder is further decomposed by absorbing hydrogen into the hydrogen-containing raw material mixed powder by holding the hydrogen-containing raw material mixed powder at a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Hydrogen absorption / decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the hydrogen-containing raw material mixed powder subjected to the hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C. in an inert gas atmosphere at a pressure of 10 to 1000 kPa,
Subsequently, the hydrogen-containing raw material mixed powder subjected to the intermediate heat treatment at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of less than 0.65 to 10 kPa By maintaining in a mixed gas atmosphere of hydrogen and an inert gas, a hydrogen-containing raw material mixed powder is subjected to heat treatment in hydrogen under reduced pressure while leaving part of the hydrogen in the mixed powder.
Thereafter, a dehydrogenation treatment is performed to forcibly release hydrogen by holding in a vacuum atmosphere at a temperature in the range of 500 to 1000 ° C. and an ultimate pressure of 0.13 kPa or less, and then to cool, A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by crushing. The rare earth magnet alloy raw material for producing the hydrogen-absorbing rare earth magnet alloy raw material powder according to claim 13, 14, 15, or 16 is homogenized under a vacuum or Ar gas atmosphere at a temperature of 600 to 1200 ° C. A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability, characterized by being a treated rare earth magnet alloy raw material. A rare earth magnet powder excellent in magnetic anisotropy and thermal stability produced by the method according to claim 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 is bonded with an organic binder or a metal binder. A method for producing a rare earth magnet. A rare earth magnet powder having excellent magnetic anisotropy and thermal stability produced by the method according to claim 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 is molded into a green compact. A method for producing a rare earth magnet, characterized in that the green compact is produced and hot pressed or hot isostatic pressed at a temperature of 600 to 900 ° C. The rare earth magnet alloy raw material according to claim 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 is atomic% (hereinafter,% indicates atomic%),
R ′ (where R ′ represents one or more of rare earth elements including Y, including cases where one or two of Dy and Tb are not included; the same applies hereinafter): 10 to 20% B: a rare earth magnet alloy raw material having a composition containing 3 to 20%, the balance being Fe and inevitable impurities,
R ′: 10 to 20%, B: 3 to 20%, M (where M is Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C And one or more of Si.): A rare earth magnet alloy raw material having a component composition of 0.001 to 5%, with the balance being Fe and inevitable impurities,
R ′: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities, or R ′: 10 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, the remainder being a rare earth magnet alloy raw material having a component composition consisting of Fe and inevitable impurities A method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability.

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